I'm a little loathe to see more work happen on HIDDEN_SETTINGS when it's such an ugly solution to begin with. Especially now that we have ​custom error reporting. It'd be so much better to see this be part of a common solution to #16435 as noted.

However, those are common sensitive values, so I'll accept the ticket for now.

There's another little issue with the docs, the docs say anything that contains PROFANITIES will match but the HIDDEN_SETTINGS regexp specifies PROFANITIES_LIST as it's pattern so as far as I know PROFANITIES_CAKE won't match in that case.